Playback device calibration based on representative spectral characteristics

ABSTRACT

A computing device may maintain a database of representative spectral characteristics. The computing device may also receive particular spectral data associated with a particular playback environment corresponding to the particular playback device. Based on the particular spectral data, the computing device may identify one of the representative spectral characteristics from the database that substantially matches the particular spectral data, and then identify, in the database, an audio processing algorithm based on a) the identified representative spectral characteristic and b) at least one characteristic of the particular playback device. The computing device may then transmit, to the particular playback device, data indicating the identified audio processing algorithm.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/089,004 filed Apr. 1, 2016, the disclosure of which is explicitlyincorporated by reference herein in its entirety. The presentapplication also incorporates by reference U.S. patent application Ser.No. 14/481,505, filed on Sep. 9, 2014, for “Audio ProcessingAlgorithms;” U.S. patent application Ser. No. 14/481,511, filed on Sep.9, 2014, for “Playback Device Calibration;” U.S. patent application Ser.No. 14/805,140, filed on Jul. 21, 2015, for “Hybrid Test Tone forSpace-Averaged Room Audio Calibration Using a Moving Microphone;” andU.S. patent application Ser. No. 15/088,994, filed on Apr. 1, 2016, for“Updating Playback Device Configuration Information Based on CalibrationData.”

FIELD OF THE DISCLOSURE

The disclosure is related to consumer goods and, more particularly, tomethods, systems, products, features, services, and other elementsdirected to media playback or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loudsetting were limited until in 2003, when SONOS, Inc. filed for one ofits first patent applications, entitled “Method for Synchronizing AudioPlayback between Multiple Networked Devices,” and began offering a mediaplayback system for sale in 2005. The Sonos Wireless HiFi System enablespeople to experience music from many sources via one or more networkedplayback devices. Through a software control application installed on asmartphone, tablet, or computer, one can play what he or she wants inany room that has a networked playback device. Additionally, using thecontroller, for example, different songs can be streamed to each roomwith a playback device, rooms can be grouped together for synchronousplayback, or the same song can be heard in all rooms synchronously.

Given the ever growing interest in digital media, there continues to bea need to develop consumer-accessible technologies to further enhancethe listening experience.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technologymay be better understood with regard to the following description,appended claims, and accompanying drawings where:

FIG. 1 shows an example media playback system configuration in whichcertain embodiments may be practiced;

FIG. 2 shows a functional block diagram of an example playback device;

FIG. 3 shows a functional block diagram of an example control device;

FIG. 4 shows an example controller interface;

FIG. 5 shows an example flow diagram for calibrating a particularplayback device;

FIG. 6 shows an example playback environment within which a playbackdevice may be calibrated;

FIG. 7 shows an example computing device in communication with anexample plurality of playback devices;

FIG. 8 shows an example portion of a database of representative spectralcharacteristics; and

FIG. 9 shows an example flow diagram for calibrating a playback device.

The drawings are for the purpose of illustrating example embodiments,but it is understood that the inventions are not limited to thearrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION

I. Overview

Examples described herein involve calibrating a playback device within aplayback environment based on representative spectral characteristics.Utilizing representative spectral characteristics may facilitate aplayback device calibration process that is, as one example, shorter induration. Other benefits are also possible.

For instance, calibration data may be aggregated by a computing device,such as a server, from the individual calibrations of numerous differentplayback devices located in numerous different playback environments.From each calibration, a spectral characteristic may be determinedcorresponding to the audio response of the given playback environment.Each spectral characteristic may represent, for example, the size,shape, furnishing, etc. of the given playback environment (e.g., room)where each playback devices was calibrated. The computing device maygather data relating to playback device characteristics from eachcalibration as well, such as the device model, hardware and/or softwareversions, zone configurations, and other manual settings correspondingto each individual playback device that is calibrated.

From the aggregated calibration data, the determined spectralcharacteristics may be grouped, mathematically and/or otherwise, into asubstantially smaller number of representative spectral characteristicsthat may capture the entire data set within a reasonable margin oferror. For instance, thousands or perhaps even millions of individualcalibrations from households and playback environments around the worldmay yield a similar number of spectral characteristics. In some cases,there may be substantial commonality and/or overlap in the distributionof spectral characteristics across all calibrated playback devices andplayback environments.

Accordingly, the computing device may analyze the calibration data anddetermine, for instance, 50 representative spectral characteristics thatmay represent, within a reasonable margin of error, the scope ofpotential playback environments in which a playback device may becalibrated. The representative spectral characteristics may bemaintained in a database on the computing device, and may be used tosimplify additional calibrations that may be performed.

For example, some of the calibrations discussed above that are used as abasis for determining the representative spectral characteristics mayinvolve recording, via a microphone, the playback of audio data from theplayback device to be calibrated. The recorded audio data may need to beof a minimum duration, such as 45 seconds, and may need to include aminimum range of frequencies, in order for the computing device to haveenough spectral data to determine the spectral characteristiccorresponding to the playback environment being calibrated. In somecases, the calibration process may require the microphone to be movedbetween different spatial locations within the playback environmentwhile the calibration audio is recorded.

Alternatively, the representative spectral characteristics discussedabove may be used by the computing device to approximate, withreasonable accuracy, the audio response of the playback environment inquestion. This may reduce the amount of spectral data that is required,and may therefore simplify the calibration procedure in one or moreways. For example, the computing device may receive spectral datacorresponding to only 10 seconds of recorded audio playback.Nonetheless, based on this sample, the computing device may identify oneof the representative spectral characteristics that substantiallymatches the received spectral data. In this way, the duration of audioplayback portion the calibration procedure may be shortened.

The requirement for less spatial data to perform a calibration of agiven playback device may result in other simplifications as well. Forinstance, it may allow the microphone to record audio data other than acalibration tone, which may have pre-determined frequency sweeps.Instead, the calibration may be based on the recorded playback of mediacontent having a narrower spectral range. In this way, a calibrationmight occur during the normal course of enjoying audio playback by theplayback device. As another example, the calibration procedure mayrequire less, or perhaps no movement of the microphone throughout theplayback environment while the calibration audio is recorded. Otherpossibilities also exist.

Once the computing device has identified a representative spectralcharacteristic in the database, it may identify an audio processingalgorithm in the database based on the identified representativespectral characteristic and at least one playback device characteristic.For instance, the database may include an entry for an audio processingalgorithm that corresponds to the identified representative spectralcharacteristic in conjunction with a particular model of playbackdevice. Other playback device characteristics may also be used.

The computing device may transmit the identified audio processingalgorithm to the playback device. The playback device may then apply theaudio processing algorithm, resulting in the playback of audio contentthat is calibrated to the particular audio characteristics of itsplayback environment.

In some cases, the use of representative spectral characteristics mayfacilitate a playback device performing a self-calibration within aplayback environment, according to some of the examples discussed above.For example, the playback device may include a microphone, which may beused to record the playback device's own playback of audio data. Theplayback device may then transmit the recorded audio playback data tothe computing device.

Because the microphone in this example is stationary, the recorded audioplayback data may include less spectral data then might otherwise berequired to accurately determine the audio response of the playbackenvironment “from scratch.” However, as discussed above, the computingdevice may identify a representative spectral characteristic from thedatabase that substantially matches the spectral data that is received.

The playback device may then receive, from the computing device, dataindicating an audio processing algorithm corresponding to the playbackenvironment. The playback device may then apply the audio processingalgorithm while playing back further audio content, resulting in audioplayback that is calibrated to the playback environment.

As indicated above, the examples involve calibrating a playback devicebased on representative spectral characteristic data. In one aspect, amethod is provided. The method involves maintaining, by a computingdevice, a database of representative spectral characteristics andreceiving, by the computing device, particular spectral data associatedwith a particular playback environment corresponding to the particularplayback device. The method also involves, based on the particularspectral data, identifying one of the representative spectralcharacteristics from the database that substantially matches theparticular spectral data and identifying, in the database, an audioprocessing algorithm based on a) the identified representative spectralcharacteristic and b) at least one characteristic of the particularplayback device. Further, the method also involves transmitting, to theparticular playback device, data indicating the identified audioprocessing algorithm.

In another aspect, a computing device is provided. The device includes aprocessor, a non-transitory computer readable medium, and programinstructions stored on the non-transitory computer readable medium that,when executed by the processor, cause the computing device to performfunctions. The functions include maintaining a database ofrepresentative spectral characteristics and receiving particularspectral data associated with a particular playback environmentcorresponding to a particular playback device. The functions alsoinclude, based on the particular spectral data, identifying one of therepresentative spectral characteristics from the database thatsubstantially matches the particular spectral data and identifying, inthe database, an audio processing algorithm based on a) the identifiedrepresentative spectral characteristic and b) at least onecharacteristic of the particular playback device. Further, the functionsinclude transmitting, to the particular playback device, data indicatingthe identified audio processing algorithm.

In yet another aspect, a playback device is provided. The deviceincludes a processor, a microphone, a non-transitory computer readablemedium, and program instructions stored on the non-transitory computerreadable medium that, when executed by the processor, cause the playbackdevice to perform functions. The functions include playing back firstaudio content in a playback environment and recording, via themicrophone, at least a portion of the played back first audio content.The functions also include transmitting the recorded audio content to acomputing device and receiving, from the computing device, dataindicating an audio processing algorithm corresponding to the playbackenvironment. Further, the functions include applying the audioprocessing algorithm while playing back second audio content in theplayback environment.

It will be understood by one of ordinary skill in the art that thisdisclosure includes numerous other embodiments. It will be understood byone of ordinary skill in the art that this disclosure includes numerousother examples. While some examples described herein may refer tofunctions performed by given actors such as “users” and/or otherentities, it should be understood that this description is for purposesof explanation only. The claims should not be interpreted to requireaction by any such example actor unless explicitly required by thelanguage of the claims themselves.

While some examples described herein may refer to functions performed bygiven actors such as “users” and/or other entities, it should beunderstood that this is for purposes of explanation only. The claimsshould not be interpreted to require action by any such example actorunless explicitly required by the language of the claims themselves.

II. Example Operating Environment

FIG. 1 shows an example configuration of a media playback system 100 inwhich one or more embodiments disclosed herein may be practiced orimplemented. The media playback system 100 as shown is associated withan example home environment having several rooms and spaces, such as forexample, a master bedroom, an office, a dining room, and a living room.As shown in the example of FIG. 1, the media playback system 100includes playback devices 102-124, control devices 126 and 128, and awired or wireless network router 130.

Further discussions relating to the different components of the examplemedia playback system 100 and how the different components may interactto provide a user with a media experience may be found in the followingsections. While discussions herein may generally refer to the examplemedia playback system 100, technologies described herein are not limitedto applications within, among other things, the home environment asshown in FIG. 1. For instance, the technologies described herein may beuseful in environments where multi-zone audio may be desired, such as,for example, a commercial setting like a restaurant, mall or airport, avehicle like a sports utility vehicle (SUV), bus or car, a ship or boat,an airplane, and so on.

a. Example Playback Devices

FIG. 2 shows a functional block diagram of an example playback device200 that may be configured to be one or more of the playback devices102-124 of the media playback system 100 of FIG. 1. The playback device200 may include a processor 202, software components 204, memory 206,audio processing components 208, audio amplifier(s) 210, speaker(s) 212,and a network interface 214 including wireless interface(s) 216 andwired interface(s) 218. In one case, the playback device 200 might notinclude the speaker(s) 212, but rather a speaker interface forconnecting the playback device 200 to external speakers. In anothercase, the playback device 200 may include neither the speaker(s) 212 northe audio amplifier(s) 210, but rather an audio interface for connectingthe playback device 200 to an external audio amplifier or audio-visualreceiver.

In one example, the processor 202 may be a clock-driven computingcomponent configured to process input data according to instructionsstored in the memory 206. The memory 206 may be a tangiblecomputer-readable medium configured to store instructions executable bythe processor 202. For instance, the memory 206 may be data storage thatcan be loaded with one or more of the software components 204 executableby the processor 202 to achieve certain functions. In one example, thefunctions may involve the playback device 200 retrieving audio data froman audio source or another playback device. In another example, thefunctions may involve the playback device 200 sending audio data toanother device or playback device on a network. In yet another example,the functions may involve pairing of the playback device 200 with one ormore playback devices to create a multi-channel audio environment.

Certain functions may involve the playback device 200 synchronizingplayback of audio content with one or more other playback devices.During synchronous playback, a listener will preferably not be able toperceive time-delay differences between playback of the audio content bythe playback device 200 and the one or more other playback devices. U.S.Pat. No. 8,234,395 entitled, “System and method for synchronizingoperations among a plurality of independently clocked digital dataprocessing devices,” which is hereby incorporated by reference, providesin more detail some examples for audio playback synchronization amongplayback devices.

The memory 206 may further be configured to store data associated withthe playback device 200, such as one or more zones and/or zone groupsthe playback device 200 is a part of, audio sources accessible by theplayback device 200, or a playback queue that the playback device 200(or some other playback device) may be associated with. The data may bestored as one or more state variables that are periodically updated andused to describe the state of the playback device 200. The memory 206may also include the data associated with the state of the other devicesof the media system, and shared from time to time among the devices sothat one or more of the devices have the most recent data associatedwith the system. Other embodiments are also possible.

The audio processing components 208 may include one or moredigital-to-analog converters (DAC), an audio preprocessing component, anaudio enhancement component or a digital signal processor (DSP), and soon. In one embodiment, one or more of the audio processing components208 may be a subcomponent of the processor 202. In one example, audiocontent may be processed and/or intentionally altered by the audioprocessing components 208 to produce audio signals. The produced audiosignals may then be provided to the audio amplifier(s) 210 foramplification and playback through speaker(s) 212. Particularly, theaudio amplifier(s) 210 may include devices configured to amplify audiosignals to a level for driving one or more of the speakers 212. Thespeaker(s) 212 may include an individual transducer (e.g., a “driver”)or a complete speaker system involving an enclosure with one or moredrivers. A particular driver of the speaker(s) 212 may include, forexample, a subwoofer (e.g., for low frequencies), a mid-range driver(e.g., for middle frequencies), and/or a tweeter (e.g., for highfrequencies). In some cases, each transducer in the one or more speakers212 may be driven by an individual corresponding audio amplifier of theaudio amplifier(s) 210. In addition to producing analog signals forplayback by the playback device 200, the audio processing components 208may be configured to process audio content to be sent to one or moreother playback devices for playback.

Audio content to be processed and/or played back by the playback device200 may be received from an external source, such as via an audioline-in input connection (e.g., an auto-detecting 3.5 mm audio line-inconnection) or the network interface 214.

The network interface 214 may be configured to facilitate a data flowbetween the playback device 200 and one or more other devices on a datanetwork. As such, the playback device 200 may be configured to receiveaudio content over the data network from one or more other playbackdevices in communication with the playback device 200, network deviceswithin a local area network, or audio content sources over a wide areanetwork such as the Internet. In one example, the audio content andother signals transmitted and received by the playback device 200 may betransmitted in the form of digital packet data containing an InternetProtocol (IP)-based source address and IP-based destination addresses.In such a case, the network interface 214 may be configured to parse thedigital packet data such that the data destined for the playback device200 is properly received and processed by the playback device 200.

As shown, the network interface 214 may include wireless interface(s)216 and wired interface(s) 218. The wireless interface(s) 216 mayprovide network interface functions for the playback device 200 towirelessly communicate with other devices (e.g., other playbackdevice(s), speaker(s), receiver(s), network device(s), control device(s)within a data network the playback device 200 is associated with) inaccordance with a communication protocol (e.g., any wireless standardincluding IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4Gmobile communication standard, and so on). The wired interface(s) 218may provide network interface functions for the playback device 200 tocommunicate over a wired connection with other devices in accordancewith a communication protocol (e.g., IEEE 802.3). While the networkinterface 214 shown in FIG. 2 includes both wireless interface(s) 216and wired interface(s) 218, the network interface 214 may in someembodiments include only wireless interface(s) or only wiredinterface(s).

The playback device 200 may also include one or more microphones 220.The microphone(s) 220 may be used to detect audio data in proximity tothe playback device 200, such as voice commands for controlling theplayback device 200. Further, the microphone(s) 220 may be used tocapture and record audio playback data from the playback device 200, orfrom one or more other playback devices in proximity to the playbackdevice 200, during a calibration procedure. Other examples and otheruses for the microphone(s) 220 are also possible.

In one example, the playback device 200 and one other playback devicemay be paired to play two separate audio components of audio content.For instance, playback device 200 may be configured to play a leftchannel audio component, while the other playback device may beconfigured to play a right channel audio component, thereby producing orenhancing a stereo effect of the audio content. The paired playbackdevices (also referred to as “bonded playback devices”) may further playaudio content in synchrony with other playback devices.

In another example, the playback device 200 may be sonicallyconsolidated with one or more other playback devices to form a single,consolidated playback device. A consolidated playback device may beconfigured to process and reproduce sound differently than anunconsolidated playback device or playback devices that are paired,because a consolidated playback device may have additional speakerdrivers through which audio content may be rendered. For instance, ifthe playback device 200 is a playback device designed to render lowfrequency range audio content (i.e. a subwoofer), the playback device200 may be consolidated with a playback device designed to render fullfrequency range audio content. In such a case, the full frequency rangeplayback device, when consolidated with the low frequency playbackdevice 200, may be configured to render only the mid and high frequencycomponents of audio content, while the low frequency range playbackdevice 200 renders the low frequency component of the audio content. Theconsolidated playback device may further be paired with a singleplayback device or yet another consolidated playback device.

By way of illustration, SONOS, Inc. presently offers (or has offered)for sale certain playback devices including a “PLAY:1,” “PLAY:3,”“PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any otherpast, present, and/or future playback devices may additionally oralternatively be used to implement the playback devices of exampleembodiments disclosed herein. Additionally, it is understood that aplayback device is not limited to the example illustrated in FIG. 2 orto the SONOS product offerings. For example, a playback device mayinclude a wired or wireless headphone. In another example, a playbackdevice may include or interact with a docking station for personalmobile media playback devices. In yet another example, a playback devicemay be integral to another device or component such as a television, alighting fixture, or some other device for indoor or outdoor use.

b. Example Playback Zone Configurations

Referring back to the media playback system 100 of FIG. 1, theenvironment may have one or more playback zones, each with one or moreplayback devices. The media playback system 100 may be established withone or more playback zones, after which one or more zones may be added,or removed to arrive at the example configuration shown in FIG. 1. Eachzone may be given a name according to a different room or space such asan office, bathroom, master bedroom, bedroom, kitchen, dining room,living room, and/or balcony. In one case, a single playback zone mayinclude multiple rooms or spaces. In another case, a single room orspace may include multiple playback zones.

As shown in FIG. 1, the balcony, dining room, kitchen, bathroom, office,and bedroom zones each have one playback device, while the living roomand master bedroom zones each have multiple playback devices. In theliving room zone, playback devices 104, 106, 108, and 110 may beconfigured to play audio content in synchrony as individual playbackdevices, as one or more bonded playback devices, as one or moreconsolidated playback devices, or any combination thereof. Similarly, inthe case of the master bedroom, playback devices 122 and 124 may beconfigured to play audio content in synchrony as individual playbackdevices, as a bonded playback device, or as a consolidated playbackdevice.

In one example, one or more playback zones in the environment of FIG. 1may each be playing different audio content. For instance, the user maybe grilling in the balcony zone and listening to hip hop music beingplayed by the playback device 102 while another user may be preparingfood in the kitchen zone and listening to classical music being playedby the playback device 114. In another example, a playback zone may playthe same audio content in synchrony with another playback zone. Forinstance, the user may be in the office zone where the playback device118 is playing the same rock music that is being playing by playbackdevice 102 in the balcony zone. In such a case, playback devices 102 and118 may be playing the rock music in synchrony such that the user mayseamlessly (or at least substantially seamlessly) enjoy the audiocontent that is being played out-loud while moving between differentplayback zones. Synchronization among playback zones may be achieved ina manner similar to that of synchronization among playback devices, asdescribed in previously referenced U.S. Pat. No. 8,234,395.

As suggested above, the zone configurations of the media playback system100 may be dynamically modified, and in some embodiments, the mediaplayback system 100 supports numerous configurations. For instance, if auser physically moves one or more playback devices to or from a zone,the media playback system 100 may be reconfigured to accommodate thechange(s). For instance, if the user physically moves the playbackdevice 102 from the balcony zone to the office zone, the office zone maynow include both the playback device 118 and the playback device 102.The playback device 102 may be paired or grouped with the office zoneand/or renamed if so desired via a control device such as the controldevices 126 and 128. On the other hand, if the one or more playbackdevices are moved to a particular area in the home environment that isnot already a playback zone, a new playback zone may be created for theparticular area.

Further, different playback zones of the media playback system 100 maybe dynamically combined into zone groups or split up into individualplayback zones. For instance, the dining room zone and the kitchen zone114 may be combined into a zone group for a dinner party such thatplayback devices 112 and 114 may render audio content in synchrony. Onthe other hand, the living room zone may be split into a television zoneincluding playback device 104, and a listening zone including playbackdevices 106, 108, and 110, if the user wishes to listen to music in theliving room space while another user wishes to watch television.

c. Example Control Devices

FIG. 3 shows a functional block diagram of an example control device 300that may be configured to be one or both of the control devices 126 and128 of the media playback system 100. As shown, the control device 300may include a processor 302, memory 304, a network interface 306, and auser interface 308. In one example, the control device 300 may be adedicated controller for the media playback system 100. In anotherexample, the control device 300 may be a network device on which mediaplayback system controller application software may be installed, suchas for example, an iPhone™, iPad™ or any other smart phone, tablet ornetwork device (e.g., a networked computer such as a PC or Mac™).

The processor 302 may be configured to perform functions relevant tofacilitating user access, control, and configuration of the mediaplayback system 100. The memory 304 may be configured to storeinstructions executable by the processor 302 to perform those functions.The memory 304 may also be configured to store the media playback systemcontroller application software and other data associated with the mediaplayback system 100 and the user.

In one example, the network interface 306 may be based on an industrystandard (e.g., infrared, radio, wired standards including IEEE 802.3,wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, 802.15, 4G mobile communication standard, and so on). Thenetwork interface 306 may provide a means for the control device 300 tocommunicate with other devices in the media playback system 100. In oneexample, data and information (e.g., such as a state variable) may becommunicated between control device 300 and other devices via thenetwork interface 306. For instance, playback zone and zone groupconfigurations in the media playback system 100 may be received by thecontrol device 300 from a playback device or another network device, ortransmitted by the control device 300 to another playback device ornetwork device via the network interface 306. In some cases, the othernetwork device may be another control device.

Playback device control commands such as volume control and audioplayback control may also be communicated from the control device 300 toa playback device via the network interface 306. As suggested above,changes to configurations of the media playback system 100 may also beperformed by a user using the control device 300. The configurationchanges may include adding/removing one or more playback devices to/froma zone, adding/removing one or more zones to/from a zone group, forminga bonded or consolidated player, separating one or more playback devicesfrom a bonded or consolidated player, among others. Accordingly, thecontrol device 300 may sometimes be referred to as a controller, whetherthe control device 300 is a dedicated controller or a network device onwhich media playback system controller application software isinstalled.

The control device 300 may also include one or more microphones 310. Themicrophone(s) 310 may be used to detect audio data in proximity to thecontrol device 300, such as voice commands for controlling the controldevice 300. Further, the microphone(s) 310 may be used to capture andrecord audio playback data from a playback device, such as the playbackdevice 200 shown in FIG. 2, during a calibration procedure of a playbackdevice 200. Other examples and other uses for the microphone(s) 310 arealso possible.

The user interface 308 of the control device 300 may be configured tofacilitate user access and control of the media playback system 100, byproviding a controller interface such as the controller interface 400shown in FIG. 4. The controller interface 400 includes a playbackcontrol region 410, a playback zone region 420, a playback status region430, a playback queue region 440, and an audio content sources region450. The user interface 400 as shown is just one example of a userinterface that may be provided on a network device such as the controldevice 300 of FIG. 3 (and/or the control devices 126 and 128 of FIG. 1)and accessed by users to control a media playback system such as themedia playback system 100. Other user interfaces of varying formats,styles, and interactive sequences may alternatively be implemented onone or more network devices to provide comparable control access to amedia playback system.

The playback control region 410 may include selectable (e.g., by way oftouch or by using a cursor) icons to cause playback devices in aselected playback zone or zone group to play or pause, fast forward,rewind, skip to next, skip to previous, enter/exit shuffle mode,enter/exit repeat mode, enter/exit cross fade mode. The playback controlregion 410 may also include selectable icons to modify equalizationsettings, and playback volume, among other possibilities.

The playback zone region 420 may include representations of playbackzones within the media playback system 100. In some embodiments, thegraphical representations of playback zones may be selectable to bringup additional selectable icons to manage or configure the playback zonesin the media playback system, such as a creation of bonded zones,creation of zone groups, separation of zone groups, and renaming of zonegroups, among other possibilities.

For example, as shown, a “group” icon may be provided within each of thegraphical representations of playback zones. The “group” icon providedwithin a graphical representation of a particular zone may be selectableto bring up options to select one or more other zones in the mediaplayback system to be grouped with the particular zone. Once grouped,playback devices in the zones that have been grouped with the particularzone will be configured to play audio content in synchrony with theplayback device(s) in the particular zone. Analogously, a “group” iconmay be provided within a graphical representation of a zone group. Inthis case, the “group” icon may be selectable to bring up options todeselect one or more zones in the zone group to be removed from the zonegroup. Other interactions and implementations for grouping andungrouping zones via a user interface such as the user interface 400 arealso possible. The representations of playback zones in the playbackzone region 420 may be dynamically updated as playback zone or zonegroup configurations are modified.

The playback status region 430 may include graphical representations ofaudio content that is presently being played, previously played, orscheduled to play next in the selected playback zone or zone group. Theselected playback zone or zone group may be visually distinguished onthe user interface, such as within the playback zone region 420 and/orthe playback status region 430. The graphical representations mayinclude track title, artist name, album name, album year, track length,and other relevant information that may be useful for the user to knowwhen controlling the media playback system via the user interface 400.

The playback queue region 440 may include graphical representations ofaudio content in a playback queue associated with the selected playbackzone or zone group. In some embodiments, each playback zone or zonegroup may be associated with a playback queue containing informationcorresponding to zero or more audio items for playback by the playbackzone or zone group. For instance, each audio item in the playback queuemay comprise a uniform resource identifier (URI), a uniform resourcelocator (URL) or some other identifier that may be used by a playbackdevice in the playback zone or zone group to find and/or retrieve theaudio item from a local audio content source or a networked audiocontent source, possibly for playback by the playback device.

In one example, a playlist may be added to a playback queue, in whichcase information corresponding to each audio item in the playlist may beadded to the playback queue. In another example, audio items in aplayback queue may be saved as a playlist. In a further example, aplayback queue may be empty, or populated but “not in use” when theplayback zone or zone group is playing continuously streaming audiocontent, such as Internet radio that may continue to play untilotherwise stopped, rather than discrete audio items that have playbackdurations. In an alternative embodiment, a playback queue can includeInternet radio and/or other streaming audio content items and be “inuse” when the playback zone or zone group is playing those items. Otherexamples are also possible.

When playback zones or zone groups are “grouped” or “ungrouped,”playback queues associated with the affected playback zones or zonegroups may be cleared or re-associated. For example, if a first playbackzone including a first playback queue is grouped with a second playbackzone including a second playback queue, the established zone group mayhave an associated playback queue that is initially empty, that containsaudio items from the first playback queue (such as if the secondplayback zone was added to the first playback zone), that contains audioitems from the second playback queue (such as if the first playback zonewas added to the second playback zone), or a combination of audio itemsfrom both the first and second playback queues. Subsequently, if theestablished zone group is ungrouped, the resulting first playback zonemay be re-associated with the previous first playback queue, or beassociated with a new playback queue that is empty or contains audioitems from the playback queue associated with the established zone groupbefore the established zone group was ungrouped. Similarly, theresulting second playback zone may be re-associated with the previoussecond playback queue, or be associated with a new playback queue thatis empty, or contains audio items from the playback queue associatedwith the established zone group before the established zone group wasungrouped. Other examples are also possible.

Referring back to the user interface 400 of FIG. 4, the graphicalrepresentations of audio content in the playback queue region 440 mayinclude track titles, artist names, track lengths, and other relevantinformation associated with the audio content in the playback queue. Inone example, graphical representations of audio content may beselectable to bring up additional selectable icons to manage and/ormanipulate the playback queue and/or audio content represented in theplayback queue. For instance, a represented audio content may be removedfrom the playback queue, moved to a different position within theplayback queue, or selected to be played immediately, or after anycurrently playing audio content, among other possibilities. A playbackqueue associated with a playback zone or zone group may be stored in amemory on one or more playback devices in the playback zone or zonegroup, on a playback device that is not in the playback zone or zonegroup, and/or some other designated device.

The audio content sources region 450 may include graphicalrepresentations of selectable audio content sources from which audiocontent may be retrieved and played by the selected playback zone orzone group. Discussions pertaining to audio content sources may be foundin the following section.

d. Example Audio Content Sources

As indicated previously, one or more playback devices in a zone or zonegroup may be configured to retrieve for playback audio content (e.g.according to a corresponding URI or URL for the audio content) from avariety of available audio content sources. In one example, audiocontent may be retrieved by a playback device directly from acorresponding audio content source (e.g., a line-in connection). Inanother example, audio content may be provided to a playback device overa network via one or more other playback devices or network devices.

Example audio content sources may include a memory of one or moreplayback devices in a media playback system such as the media playbacksystem 100 of FIG. 1, local music libraries on one or more networkdevices (such as a control device, a network-enabled personal computer,or a networked-attached storage (NAS), for example), streaming audioservices providing audio content via the Internet (e.g., the cloud), oraudio sources connected to the media playback system via a line-in inputconnection on a playback device or network devise, among otherpossibilities.

In some embodiments, audio content sources may be regularly added orremoved from a media playback system such as the media playback system100 of FIG. 1. In one example, an indexing of audio items may beperformed whenever one or more audio content sources are added, removedor updated. Indexing of audio items may involve scanning foridentifiable audio items in all folders/directory shared over a networkaccessible by playback devices in the media playback system, andgenerating or updating an audio content database containing metadata(e.g., title, artist, album, track length, among others) and otherassociated information, such as a URI or URL for each identifiable audioitem found. Other examples for managing and maintaining audio contentsources may also be possible.

The above discussions relating to playback devices, controller devices,playback zone configurations, and media content sources provide onlysome examples of operating environments within which functions andmethods described below may be implemented. Other operating environmentsand configurations of media playback systems, playback devices, andnetwork devices not explicitly described herein may also be applicableand suitable for implementation of the functions and methods.

III. Playback Device Calibration

As further discussed in the related application Ser. Nos. 14/481,505,14/481,511, and 14/805,140, which are incorporated herein by reference,an example calibration of a playback device in a playback environmentmay generally involve the playback device playing back a first audiosignal, which is detected and recorded by a microphone as a second audiosignal. For instance, the playback device may be the playback device 200shown in FIG. 2, and the microphone 310 may be part of a control device300, such as a smartphone. In other examples, the microphone may be themicrophone 220 of the playback device 200, or of another playbackdevice, among other possibilities.

The first audio signal may be a test or calibration tone having aparticular spectral profile. Different test tones may be stored and usedbased on the particular configuration of the playback device 200, ananticipated genre of music to be played, the particular characteristicsof the playback environment (e.g., room size), etc. After detecting thesecond audio signal, the control device 300 may, in some examples, senddata indicating the second audio signal to a computing device. Thecomputing device may be a server that determines, based on the dataindicating the second audio signal, an audio processing algorithm foruse by the playback device 200 in the playback environment, which may betransmitted back to the playback device 200.

The audio processing algorithm determined for the playback device 200 ina given calibration is based on several inputs. First, each calibrationof the playback device 200 may generally aim to calibrate the playbackdevice 200 according to a target frequency response curve. The targetfrequency response curve may correspond to a frequency response that isconsidered good-sounding, or pleasing to a typical listener. The targetfrequency response curve may vary based on the model of playback device200 (e.g., size), the orientation of the playback device 200 (e.g.,vertical or horizontal), or other configurations states of the playbackdevice 200 (e.g., bonded with another playback device). The computingdevice may store target frequency response curves in a database for eachpotential configuration, or they may be stored on the playback device200, the controller device 300, or more than one of the above.

Further, the microphone that detects the first audio signal, whether itis the microphone 310 on the control device, the microphone 220 on theplayback device 200, or a microphone on another playback device, has itsown audio characteristics. For example, the response of microphone 310may depend on the type and model of control device 300 used. Themicrophone response curve may also be stored in the database on thecomputing device, or elsewhere. With this information, the second audiosignal that is detected by the microphone 310 may be normalizedconsidering the known audio characteristics of the microphone 310. Otherknown adjustments to the second audio signal may also be applied. Forinstance, in some cases, the control device 300 may be configured todetect the presence of a protective case, and may obtain from thecomputing device information regarding the effects of the case on themicrophone's audio characteristics. Again, this information may bestored in the database on the computing device. Other possibilities alsoexist.

Additionally, the second audio signal detected by the microphone 310will reflect a frequency response corresponding to the playbackenvironment where the playback device is located. Unlike theconfiguration of the playback device 200, the target frequency responsecurve, microphone response curve, and other device-based inputs, whichmay be generally known, the frequency response of the playbackenvironment may represent an unknown variable in each calibration. Forinstance, the frequency response of the playback environment may bebased on the size of a given room, its construction materials, thefurnishings of the room and their location with in the room, among otherfactors. Consequently, it may be determined empirically during thecalibration using the microphone 310.

Based on at least some of the calibration inputs discussed above, thecomputing device may determine an audio processing algorithm that, whentransmitted to and applied by the playback device 200 in the playbackenvironment, will cause audio playback by the playback device 200 toapproach or meet the target frequency response curve. More or fewercalibration inputs than those described above may be used. However, toobtain a playback device calibration that is specific to the playbackenvironment, some calibration procedures may require a minimum amount ofrecorded spectral data from the playback environment for the computingdevice to determine an accurate response curve for the playbackenvironment. For instance, some calibrations may require 45 seconds ofrecorded playback of the test tone, which may proceed through adesignated series of spectral sweeps. Further, the calibration mayrequire recorded spectral data from multiple locations in the playbackenvironment, necessitating movement of the microphone about theenvironment by a user, for instance.

FIG. 6 illustrates an example playback environment 600 including acontrol device 602, a playback device 604, and a playback device 606.The control device 602, which may be coordinating and/or performing atleast a portion of the calibration, may be similar to the control device300 of FIG. 3. The playback devices 604 and 606 may both be similar tothe playback device 200 of FIG. 2, and one or both may be calibratedaccording to the examples discussed herein. FIG. 6 also illustrates anexample path 608 from a first location (a) to a second location (b)within the playback environment 600, which may represent the movement ofthe control device 602 during a calibration.

FIG. 6 also shows a computing device 610, which may collect, store, andtransmit the calibration information described herein. The computingdevice 610 may be a server in communication with a media playback systemthat includes the playback devices 604 and 606. The computing device 610may also be in communication, either directly or indirectly, with thecontrol device 602. While the discussions below may refer to theplayback environment 600 of FIG. 6, it should be appreciated that theplayback environment 600 is only one example of a playback environmentwithin which a playback device may be calibrated. Other examples arealso possible.

The computing device 610 may receive and store in the databaseadditional information relating to each calibration event. Theinformation may be transmitted by each of the playback devices that iscalibrated, whether in playback environment 600 or elsewhere.Additionally or alternatively, the information may be transmitted by acontrol device involved in the calibration. For instance, a givenplayback device and/or control device may transmit information regardingthe date and time of a given calibration, an identification of theplayback device including the make, model, and serial number, which mayfurther indicate the “age” of the playback device (since it wasmanufactured), the zone configuration of the playback device, such as agrouping or pairing state, the software version of the playback device,the hardware and software version of a given control device. Numerousother examples are also possible.

In addition, the computing device 610 may receive and store results fromeach calibration in the database. For example, the computing device maystore the determined response curve for each playback environment inwhich a playback device is calibrated, including more specificinformation such as the approximate room size or the proximity of anobstructive object to the playback device, which may be detected by themicrophone. Further, the computing device 610 may receive and store theaudio processing algorithm that is implemented by each playback deviceas a result of each calibration. For instance, the computing device 610may receive and store the specific filter coefficients that are appliedby each playback device. As another example, the computing device 610may receive and store a difference metric for each calibration, whichmay include an indication of how significantly the sound calibration ofthe playback device changed as a result of the calibration. Thecomputing device 610 may also receive and store information regardingfailed calibration attempts, including the reason for the failure, ifknown. Other examples are also possible.

In some embodiments, the computing device 610 may be a server that ismaintained and operated by the company that sells the playback devicesbeing calibrated, such as SONOS, Inc. Alternatively, a third party maymaintain and operate the server on behalf of the playback devicecompany. In other examples, a company may employ the methods describedherein across multiple different types of speaker systems, which mayinclude playback devices that are made and sold by various differentcompanies. For example, the server might be operated by an audio contentprovider, or audio content curating service, among other possibilities.

The calibration information discussed above may be provided to thecomputing device 610 in a variety of ways. For example, the calibrationdata may be transmitted to the server directly in real time, during orimmediately following each calibration that takes place. However, ifthere are a relatively large number of calibrations across many devices,this may create bandwidth issues at the computing device 610. Therefore,each playback device may locally store and update a calibration filecontaining the data discussed above. The calibration file may then beperiodically requested (“pulled”) by the computing device 610, perhapsas part of a playback device diagnostic event or a software update.Alternatively, the calibration file may be transmitted (“pushed”) to thecomputing device 610 by the playback device as part of a diagnosticevent or a software update. The calibration file might also betransmitted in response to a manual commend, such as a user input. Otherexamples are also possible.

In addition to receiving and storing the calibration data, the computingdevice 610, may also receive and store information from each playbackdevice that is not necessarily related to an individual calibrationevent. For example, the computing device 610 may receive and storeplayback device characteristics such as user account(s) data associatedwith the playback device (e.g., geography, age, gender, etc.), playbackhistory of the playback device and associated data (e.g., listeningduration, audio quality, genres, favorites, media sources, etc.) and anymanual settings present on the playback device at the time ofcalibration, such as a manually adjusted equalization (EQ). Otherpossibilities also exist.

In some embodiments, a calibration check may be performed on a givenplayback device. For example, each playback device has a targetfrequency response curve representing how audio content should soundwhen played in the particular environment by the playback device, oncecalibrated. Thus, it may be possible to perform a coarse check todetermine whether the current calibration of the playback device iswithin a certain margin of error of the target frequency response curve.For example, the coarse check may include recording audio content from acalibration tone that is simplified in its content, duration, or both.Alternatively, recorded playback of media content may be used for thecoarse check. If the current calibration is not within the margin oferror, which may be, for example, 10 percent, it may indicate that acalibration should be performed. The user may then be prompted tocalibrate the playback device via the interface 308 of the controldevice 300. In some examples, periodic calibration checks may beperformed on a given playback device, such as once per month.

Further, the computing device 610 may receive and store data that mayindicate a level of listener satisfaction with each calibration. Forinstance, if two calibrations for the same device occur in relativelyclose proximity to each other, with few other variables changing, it mayindicate that the listener was dissatisfied with the first calibration.As another example, the computing device may receive an indication thatthe audio response of the playback device has been manually adjustedfollowing a calibration, which may again indicate that the calibrationdid not meet the listener's expectations.

On the other hand, the computing device 610 may receive data indicatingan increase playback activity following a calibration. This may indicateincreased listener satisfaction with the calibration. Further, if thecomputing device 610 does not receive any recalibration data, nor anydata indicating a manual EQ change, it may imply that the user wassatisfied. As another example, a simple survey inquiring whether thelistener was satisfied with the calibration, or noticed an improvement,may be provided via an interface of the control device 602. Othermeasures for determining listener satisfaction with a given calibrationalso exist.

Finally, although the examples described herein may primarily involvethe computing device 610 acting as a centralized server receiving andstoring calibration information from numerous playback devices acrossnumerous playback environments, it should be understood that thecollection, storage, and transmission of calibration informationdiscussed in all of the examples herein may be carried out within asingle playback system, by one or more of the playback devices andcontrollers of the individual system, either temporarily or for anextended period of time. For example, calibration data may be aggregatedfor all playback device calibrations within a single playback system,and may be stored among one or more of the playback devices or otherdevices within the playback system. The aggregated calibration data maythen be transmitted to another computing device in communication withmultiple playback systems. Other examples are also possible.

a. Playback Device Calibration Based on Representative SpectralCharacteristics

As noted above, examples discussed herein involve calibrating a playbackdevice within a playback environment based on representative spectralcharacteristics. Utilizing representative spectral characteristics mayfacilitate a playback device calibration process that is, for instance,shorter in duration. Other benefits are also possible.

Methods 500 and 900 shown in FIGS. 5 and 9 present embodiments ofmethods that can be implemented within an operating environmentinvolving, for example, the media playback system 100 of FIG. 1, one ormore of the playback device 200 of FIG. 2, and one or more of thecontrol device 300 of FIG. 3. Methods 500 and 900 may include one ormore operations, functions, or actions as illustrated by one or more ofblocks 502-510 and 902-910. Although the blocks are illustrated insequential order, these blocks may also be performed in parallel, and/orin a different order than those described herein. Also, the variousblocks may be combined into fewer blocks, divided into additionalblocks, and/or removed based upon the desired implementation.

In addition, for the methods 500, 900, and other processes and methodsdisclosed herein, the flowchart shows functionality and operation of onepossible implementation of present embodiments. In this regard, eachblock may represent a module, a segment, or a portion of program code,which includes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer readable medium, forexample, such as a storage device including a disk or hard drive. Thecomputer readable medium may include non-transitory computer readablemedium, for example, such as computer-readable media that stores datafor short periods of time like register memory, processor cache andRandom Access Memory (RAM). The computer readable medium may alsoinclude non-transitory media, such as secondary or persistent long termstorage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. The computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device. Inaddition, for the methods 500, 900 and other processes and methodsdisclosed herein, each block in FIGS. 5 and 9 may represent circuitrythat is wired to perform the specific logical functions in the process.

At block 502 of the method 500, a computing device may maintain adatabase of representative spectral characteristics. The representativespectral characteristics may be based on a plurality of spectral datacorresponding to the plurality of playback environments. For instance,the computing device may be the computing device 610 shown in FIG. 6,which may act as a central server in communication with the plurality ofplayback devices.

FIG. 7 shows another example of the computing device according to someof the examples discussed herein. In FIG. 7, the computing device isshown as the computing device 701, in communication with a particularplayback device 702, which is to be calibrated in a particular playbackenvironment 703. The particular playback device 702 may be similar tothe playback device 200 shown in FIG. 2, as well as the playback devices604 and 606 shown in FIG. 6. FIG. 7 also shows a plurality of playbackdevices 704 a, 704 b, and 704 c, located respectively within differentplayback environments 705 a, 705 b, and 705 c. Each of these playbackdevices may also be similar to the playback device 200 shown in FIG. 2.

The computing device 701 may receive a plurality of spectral datacorresponding to the plurality of playback environments 705 a, 705 b,and 705 c. The received spectral data may be the result of individualcalibrations of the playback devices 704 a, 704 b, and 705 c, inresponse to which the computing device 701 may have determined an audioprocessing algorithm for use by each playback device. In each case, thereceived spectral data may indicate the response curve for therespective playback environment in which each respective playback devicewas calibrated. Further, the computing device 701 may store the receivedspectral data, as well as the determined audio processing algorithm, foreach calibration.

The spectral data received from each of the plurality of playbackdevices 704 a, 704 b, and 704 c may be recorded audio playback data. Forinstance, a given playback device may play a pre-determined calibrationtone during its calibration event. The calibration tone may be recordedby a microphone 310 of an associated control device 300, a microphone220 of the given playback device, or another microphone, and thentransmitted to the computing device 701. Additionally or alternatively,the recorded audio playback data may include recorded audio playback ofmedia content. For example, a microphone as discussed above may, duringthe normal course of media content playback by the given playbackdevice, record the media content playback and then transmit the recordedaudio playback data to the computing device 701. Other examples are alsopossible.

In some instances, each recorded audio playback data in the plurality ofrecorded audio playback data may have the same duration. In other words,each calibration event, across all of the playback devices in theplurality of playback devices, may include the playback and recording ofaudio data having the same duration. The duration may be, for example,45 seconds, although other durations are also possible.

Moreover, the plurality of playback devices shown in FIG. 7 mayrepresent far more playback devices than the three depicted. In somecases, the computing device 701 may receive spectral data correspondingto hundreds of thousands, perhaps even millions, of playback deviceslocated in different playback environments around the world. Based onspectral data received from this relatively large sample of playbackenvironments, the computing device 701 may determine a finite number ofrepresentative spectral characteristics that may simplify the scope ofpossible results for a given calibration, and thus may simplify thecalibration process.

For example, in some cases, the computing device 701 may determine thatthe response curves for all of the calibrated playback environments maybe grouped, mathematically, into a finite number of representativeresponse curves. For instance, the computing device 701 may determinethat there are 50 representative response curves that capture all, ornearly all, of the received spectral data within a 5% confidence margin.In some cases, extreme outliers may be ignored. As additional examples,the computing device 701 may determine 12 representative responsecurves, or perhaps 100. As noted above, this finite number ofrepresentative spectral characteristics may be used in some futurecalibrations. The total number of representative spectralcharacteristics may depend on a combination of the overall distributionof the received spectral data, the level of accuracy desired, amongother factors.

As another example, the representative spectral characteristics may bedetermined based on other data, as an alternative to or in addition to astrictly mathematical analysis. For instance, the representativespectral characteristics may be determined based, in part, on anindication within the data set that, for a given set of the receivedspectral data, a similar audio processing algorithm applied by eachrespective playback device tends to provide a similar level of listenersatisfaction with the calibration. Listener satisfaction with a givencalibration may be determined or approximated as noted above. Otherbases for determining the representative spectral data also exist.

Other characteristics corresponding to each playback device 704 a, 704b, and 705 c may be collected for each calibration as well, in additionto the received spectral data. For example, each calibration may beassociated with a given model number, serial number, and/or softwareversion of the calibrated playback device, or of a control device 300that may be involved in the calibration. The playback devicecharacteristics may also include manual settings of the playback deviceat the time of calibration, such as a zone configuration or a manuallyadjusted EQ. The computing device 701 may also store the results of eachcalibration as well, including the determined response curve for eachplayback environment and the determined audio processing algorithm.Other examples are also possible.

These additional playback device characteristics may also inform thedetermination of the representative spectral characteristics as well.For instance, each playback device that is calibrated may have an audiocharacteristic that is generally known, based on the model of theplayback device. The same may be true for the microphones used in thecalibration process, whether in a control device or in the playbackdevice. Based this data, the computing device 701 may normalize thereceived spectral data from each calibration to be independent of themodel of playback device or control device involved in the calibration.

FIG. 8 illustrates a portion of an example database 800 maintained bythe computing device 701, within which the representative spectralcharacteristics discussed above may be stored. As shown, the portion ofthe database 800 may include a plurality of entries 801 a, 801 b, 801 c,and 801 d each representing one of the determined representativespectral characteristics. The representative spectral characteristicsmay be stored in the database 800 as mathematical representationsh_(room) ⁻¹(t)−1, h_(room) ⁻¹(t)−2, h_(room) ⁻¹(t)−3, and h_(room)⁻¹(t)−4, each describing the spectral characteristic of a representativeplayback environment.

Further, the portion of the database 800 contains a second columncontaining entries 802 a, 802 b, 802 c, and 802 d, each representing aplayback device characteristic. In the example shown in FIG. 8, theplayback device characteristic is a device model, in this case a “PLAY:3” model playback device for each entry. The plurality of entries 802 a,802 b, 802 c, and 802 d correspond, respectively, to the entries 801 a,801 b, 801 c, and 801 d. Other device models are also possible.Moreover, different playback device characteristics, such as zoneconfiguration, for example, are also possible in the second column ofthe database 800. In each case, the playback device characteristic usedmay result in different corresponding entries in further columns of thedatabase 800.

For example, a third column in the portion of the example database 800contains a series of entries 803 a, 803 b, 803 c, and 803 d. Each entryin the third column contains coefficients for an audio processingalgorithm determined based on the corresponding representative spectralcharacteristic and the playback device characteristic in the first twocolumns. For example, the determined representative spectralcharacteristic 801 a, in conjunction with the playback devicecharacteristic 802 a, i.e., a “PLAY: 3” model device, may correspond toan audio processing algorithm 803 a represented by coefficients w₁, x₁,y₁, and z₁, and so on for the additional rows in the database 800.

The portion of the database 800 shown in FIG. 8 represents only oneexample of a database of representative spectral characteristics thatthe computing device 701 may populate and maintain. In some instances,more than one playback device characteristic may be used, such as devicemodel and zone configuration, in the determination of the audioprocessing algorithms. Further, the representative spectralcharacteristics may be stored in a different format or mathematicalstate (i.e., inverse vs. non-inverse functions). In another example, theaudio processing algorithms may be stored as functions and/orequalization functions. Other examples are also possible.

Whatever its format and content, the database 800 of representativespectral characteristics may be used to simplify a calibration procedurefor a particular playback device located in a particular playbackenvironment. Returning to FIG. 6, the particular playback device may be,for instance, the playback device 604, which may be similar to theplayback device 200 shown in FIG. 2. Further, the particular playbackenvironment may be the playback environment 600 shown in FIG. 6.

At block 504 of the method 500, the computing device 610 may receiveparticular spectral data associated with the particular playbackenvironment 600, corresponding to the particular playback device 604.For example, the control device 602 shown in FIG. 6 may initiate acalibration procedure, and the playback device 604 may begin playback ofa predetermined calibration tone that is recorded by a microphone of thecontrol device 602. Thus, the particular spectral data may includerecorded audio playback data. The particular spectral data mayadditionally or alternatively include recorded audio playback of mediacontent, as discussed above.

As noted above, a goal of capturing audio playback by a playback deviceduring calibration is to determine the spectral characteristic of theplayback environment in question. The calibration of the particularplayback device 604 in the present example has, by virtue of thedatabase 800, a finite number of known representative spectralcharacteristics as a potential result. Consequently, the computingdevice 610 may be able to identify one of the representative spectralcharacteristics based on relatively less spectral data than some othercalibration procedures, which may involve empirically determining thespectral characteristic of a given playback environment “from scratch.”

Accordingly, at block 506, based on the particular spectral data, thecomputing device 610 may identify one of the representative spectralcharacteristics from the database 800 that substantially matches theparticular spectral data. For instance, the computing device 610 maymathematically determine the best fit for the particular spectral dataamong the representative spectral characteristics. This may represent arelatively high probability that the particular playback environment 600corresponds to the identified representative spectral characteristic.

The requirement for less particular spectral data in the calibration ofparticular playback device 604 may lead to simplification of thecalibration process in multiple ways. For instance, as noted above, somecalibrations may require 45 seconds of recorded audio playback todetermine the spectral characteristic of a given playback environment.However, in the present example, the computing device 610 may requireparticular spectral data that is shorter in duration. For example, thecomputing device 610 may be able to identify, with relative accuracy, arepresentative spectral characteristic that substantially matches theparticular playback environment 600 based on only 10 seconds of recordedaudio playback from particular playback device 604.

Further, in some cases, the control device 602 might not record theaudio playback from the particular playback device consecutively toobtain the necessary spectral data. For instance, rather than recording10 consecutive seconds, the control device 602 might record briefsnippets of audio playback each time the control device 602 is in adifferent location in the particular playback environment 600, andwithin a predefined range of the particular playback device 604. Thesesnippets, collectively, may have a relatively short duration, yet theymay contain sufficient spectral data for the computing device 610 toidentify a representative spectral characteristic.

The particular spectral data may also represent a narrower frequencyrange than might otherwise be required for to determine a playbackenvironment's audio characteristic. Nonetheless, the computing device610 may identify, with relative accuracy, one of the representativespectral characteristics in the database 800. The ability of thecomputing device 610 to identify a representative spectralcharacteristic based on a narrower frequency range may allow for thereduced duration of recorded audio playback, as noted above. Forexample, instead of recording a pre-determined calibration tone for itsentire duration, which may include an extensive sampling of frequencies,the control device 602 may record, and the computing device 610 mayreceive, only a first portion of the calibration tone. The first portionof the calibration tone may include a coarse sampling of frequenciesthat may provide sufficient spectral data for the computing device 610to make a relatively accurate identification of a representativespectral characteristic. Accordingly, some calibration tones may bearranged in this way, such that the may be used for a either a fullduration calibration as discussed above, or a shortened calibration asdescribed in the present example.

In addition, the ability of the computing device 610 to identify arepresentative spectral characteristic based on less frequency data mayfacilitate the use of media content to calibrate the particular playbackdevice 604, rather than a calibration tone. For example, while somemedia content may not contain the spectral range of a full-durationcalibration tone, it may contain sufficient spectral data to allow thecomputing device 610 to identify a representative spectralcharacteristic for the particular playback environment 600, as notedabove. In this way, calibration of the particular playback 604 may beperformed during the normal course of listening to media content.

Still further, the particular spectral data may include less spatialdata than the spectral data obtained in some other calibrationprocedures. As discussed above with reference to FIG. 6, somecalibrations may involve the control device 602 and it associatedmicrophone being moved throughout the playback environment 600. As shownin FIG. 6, the control device 602 may be moved on the circuitous path608 from point (a) to point (b), recording the spectral data atdifferent spatial locations within the playback environment 600.

In contrast, calibration of the particular playback device 604 in thepresent example may not require the same degree of spatial sampling. Forinstance, the control device 602 may be moved on shorter, direct pathfrom point (a) to point (b) while recording the audio playback data.Further, in some examples the control device 602 may not be moved withinthe particular playback environment 600 at all. Accordingly, this mayfacilitate a stationary microphone in the particular playbackenvironment 600 capturing audio playback data during the calibrationprocess. Thus, a microphone located on the particular playback device604, or perhaps on another playback device, such as the playback device606, may be used.

The amount of particular spectral data that is required to identify asubstantial match with one of the representative spectral characteristicmay be determined in a number of ways. For example, the computing device610 may determine, based on the known distribution of representativespectral characteristics and a known calibration tone to be used, that aminimum of 10 seconds of particular spectral data is required toidentify a matching representative spectral characteristic with 95%accuracy.

In other examples, the control device 602, or perhaps a playback devicewithin with particular playback environment 600, may transmit theparticular spectral data to the computing device 610 as it is capturedduring the calibration process. The computing device 610 may thendetermine, on an ongoing basis, the level of confidence in identifying arepresentative spectral characteristic that substantially matches thereceived particular spectral data. When the level of confidence reachesa threshold, such as 95%, the computing device 610 may transmit amessage to one or both of the particular playback device 604 and thecontrol device 602 that no more particular spectral data is required,and either the playback or recording, or both, may be discontinuedaccordingly. Other possibilities also exist.

It is possible that, in some instances, the computing device 610 maydetermine that the particular spectral data received from the particularplayback device 604 does not substantially match any of therepresentative spectral characteristics in the database 800. Forexample, the particular playback environment may not be sufficientlysimilar to other playback environments in which playback devices havebeen calibrated, and the data obtained. In this situation, the user maybe informed, via the control device, that his or her playbackenvironment is unique. Further, the user may be prompted to initiate acalibration procedure “from scratch” that includes a more completespectral analysis of the particular playback environment. Other examplesare also possible.

At block 508, the computing device 610 may identify, in the database800, an audio processing algorithm based on the identifiedrepresentative spectral characteristic and at least one characteristicof the particular playback device 604. For instance, the computingdevice may identify the representative spectral characteristic h_(room)⁻¹(t)−3, corresponding to entry 801 c in the database 800. Further, thecomputing device 610 may determine that the particular playback device604 is a “PLAY: 3” model, corresponding to the entry 802 c in thedatabase 800. Based on this data, the computing device 610 may identifythe audio processing algorithm at entry 803 c in the database 800,represented by the coefficients w₃, x₃, y₃, and z₃.

Other examples are also possible. For instance, the database 800 mayinclude other entries corresponding to representative spectralcharacteristic h_(room) ⁻¹(t)−3 in conjunction with different playbackdevice characteristics, such as an example in which the particularplayback device 604 is a different model, such as a “PLAY: 5.” This mayresult in the computing device 610 identifying a different audioprocessing algorithm within the database 800. As noted above, multipleplayback device characteristics may be used in some cases.

At block 510, the computing device 610 may transmit, to the particularplayback device 604, data indicating the identified audio processingalgorithm. The particular playback device 604 may then apply theidentified audio processing algorithm when playing back audio content inthe particular playback environment 600.

In some cases, the computing device 610 may store an indication of theidentified audio processing algorithm, which may be associated with theparticular playback environment 600. This may allow the computing device610 to transmit data indicating the identified audio processingalgorithm to a second particular playback device corresponding to theparticular playback environment 600, such as the playback device 606. Inthis way, the particular playback environment 600 may be calibrated oncefor the first particular playback device 604, and then the resultingaudio processing algorithm may be transmitted to the second particularplayback device 606 that may be currently located within the particularplayback environment 600. A similar process may be used for a secondplayback device that may be later added to the particular playbackenvironment 600.

In some examples, the playback device characteristics of the first andsecond particular playback devices might not be the same. In thissituation, the computing device 610 may, based on the identifiedrepresentative spectral characteristic and the playback devicecharacteristic of the second particular playback device 606, update theidentified audio processing algorithm and then transmit the updatedaudio processing algorithm to the second particular playback device 606.Alternatively, the computing device 610 may identify a different audioprocessing algorithm from the database 800. Other examples are alsopossible.

In another embodiment, the computing device 610 may cause an indicationof the identified audio processing algorithm to be stored at theparticular playback device 604. For example, the audio processingcoefficients w₃, x₃, y₃, and z₃ may be stored in memory on the playbackdevice 604. This may allow the particular playback device 604 to bemoved to another playback environment and perhaps recalibrated, and thenmoved back to the particular playback environment 600. In thissituation, the particular playback device 604 may apply the previouslyidentified audio processing algorithm stored in its memory, and thusregain its previous calibration to the particular playback environment600. Further, the particular playback device 604 may transmit the storedindication of the identified audio processing algorithm to otherplayback devices located within in the particular playback environment600. Other examples are also possible.

b. Playback Device Self-Calibration Based on Representative SpectralCharacteristics

Combining several of the examples discussed above, an example playbackdevice may perform a self-calibration based on representative spectralcharacteristics. The playback device may be, for example, the playbackdevice 604 shown in FIG. 6, which may be similar to the playback device200 shown in FIG. 2. The playback device 604 may include a processor202, a microphone 220, and a non-transitory computer readable medium,such as memory 206. The memory 206 may include program instructionsstored thereon that, when executed by the processor 202, cause theplayback device 604 to perform functions such as those depicted in theflowchart 900 shown in FIG. 9.

For example, at block 902 of the method 900, the playback device 604 mayplay back first audio content in a playback environment, such as theplayback environment 600. The first audio content may include apre-determined calibration tone. Additionally or alternatively, thefirst audio content may include the playback of media content, asdiscussed above. For instance, the first audio content may be audiocontent that that playback device 604 is already playing, irrespectiveof any indication that a calibration procedure has been initiated.

At block 904, the playback device 604 may record, via the microphone220, at least a portion of the played back first audio content. At block906, the playback device 604 may transmit the recorded audio content toa computing device, such as the computing device 610 shown in FIG. 7.Further, the playback device 604 may also transmit playback devicecharacteristic information to the computing device 610 that correspondsto the playback device 604.

The playback device characteristic information may include any of theinformation and data noted above, such as the date and time of a givencalibration, the serial number of the playback device 604, the zoneconfiguration of the playback device 604, the software version of theplayback device 604, the hardware and software version of a controldevice 602 associated with the playback device 604, the user accountsassociated with the playback device 604, playback history and associateddata (genres, favorites, etc.) and any manual settings present on theplayback device 204 at the time of calibration, such as a manuallyadjusted EQ. Numerous other examples are also possible.

In some examples, the computing device 604 may receive an indicationfrom the computing device 610 that a particular duration of recordedaudio content is to be recorded and transmitted. Alternatively, theplayback device 604 may record and transmit recorded audio content tothe computing device 610 continuously until it receives an indicationfrom the computing device 610 that no further recorded audio content isrequired. In response, the playback device 604 may discontinue playbackof the first audio content, discontinue recording the played back firstaudio content, or both.

At block 908, the playback device 604 may receive, from the computingdevice 610, data indicating an audio processing algorithm correspondingto the playback environment 600. The audio processing algorithm may bedetermined by the computing device 610 based on representative spectralcharacteristics, as well as one or more of the playback devicecharacteristics transmitted by the playback device 604, according theexamples and discussion above.

Further, the computing device 604 may store the received indication ofthe audio processing algorithm corresponding to the playback environment600 in memory 206. This may allow the playback device 604 to, forinstance, recall the determined audio processing algorithm if it ismoved and calibrated elsewhere, and then returned to the playbackenvironment 600. Additionally, the playback device 604 may transmit dataindicating the audio processing algorithm to other playback devices inthe playback environment 600, such as playback device 606, as furtherdiscussed above.

At block 910, the playback device 604 may apply the audio processingalgorithm while playing back second audio content in the playbackenvironment 600. This may result in the calibration of the playbackdevice 604 and an improved listening experience. As noted in theexamples above, the calibration described may be performed by theplayback 604 relatively quickly. In some cases, the calibration may alsobe relatively unnoticeable to a listener, as it may be performed duringthe normal course of playing back audio content.

In some examples, the playback device 604 may be configured to perform aself-calibration according to the examples above at a given time. Forinstance, the playback device 604 may perform a self-calibration every 6months, or whenever it receives a software update, or whenever its zoneconfiguration is updated. As another example, the playback device 604may be configured to perform a self-calibration at a certain time ofday, on a certain day of the week. For instance, playback device 604 mayperform a self-calibration during the middle of the day, when nobody isexpected to be present in the playback environment 600. In thissituation, the playback device 604 may opt to self-calibrate using apre-determined calibration tone, which may otherwise be disrupting iflisteners are present. Numerous other examples, alone or in combinationwith those above, are also possible

IV. Conclusion

The description above discloses, among other things, various examplesystems, methods, apparatus, and articles of manufacture including,among other components, firmware and/or software executed on hardware.It is understood that such examples are merely illustrative and shouldnot be considered as limiting. For example, it is contemplated that anyor all of the firmware, hardware, and/or software aspects or componentscan be embodied exclusively in hardware, exclusively in software,exclusively in firmware, or in any combination of hardware, software,and/or firmware. Accordingly, the examples provided are not the onlyway(s) to implement such systems, methods, apparatus, and/or articles ofmanufacture.

As indicated above, the examples involve calibrating a playback devicebased on representative spectral characteristic data. In one aspect, amethod is provided. The method involves maintaining, by a computingdevice, a database of representative spectral characteristics andreceiving, by the computing device, particular spectral data associatedwith a particular playback environment corresponding to the particularplayback device. The method also involves, based on the particularspectral data, identifying one of the representative spectralcharacteristics from the database that substantially matches theparticular spectral data and identifying, in the database, an audioprocessing algorithm based on a) the identified representative spectralcharacteristic and b) at least one characteristic of the particularplayback device. Further, the method also involves transmitting, to theparticular playback device, data indicating the identified audioprocessing algorithm.

In another aspect, a computing device is provided. The device includes aprocessor, a non-transitory computer readable medium, and programinstructions stored on the non-transitory computer readable medium that,when executed by the processor, cause the computing device to performfunctions. The functions include maintaining a database ofrepresentative spectral characteristics and receiving particularspectral data associated with a particular playback environmentcorresponding to a particular playback device. The functions alsoinclude, based on the particular spectral data, identifying one of therepresentative spectral characteristics from the database thatsubstantially matches the particular spectral data and identifying, inthe database, an audio processing algorithm based on a) the identifiedrepresentative spectral characteristic and b) at least onecharacteristic of the particular playback device. Further, the functionsinclude transmitting, to the particular playback device, data indicatingthe identified audio processing algorithm.

In yet another aspect, a playback device is provided. The deviceincludes a processor, a microphone, a non-transitory computer readablemedium, and program instructions stored on the non-transitory computerreadable medium that, when executed by the processor, cause the playbackdevice to perform functions. The functions include playing back firstaudio content in a playback environment and recording, via themicrophone, at least a portion of the played back first audio content.The functions also include transmitting the recorded audio content to acomputing device and receiving, from the computing device, dataindicating an audio processing algorithm corresponding to the playbackenvironment. Further, the functions include applying the audioprocessing algorithm while playing back second audio content in theplayback environment.

Additionally, references herein to “embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment can be included in at least one example embodiment of aninvention. The appearances of this phrase in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. As such, the embodiments described herein, explicitly andimplicitly understood by one skilled in the art, can be combined withother embodiments.

The specification is presented largely in terms of illustrativeenvironments, systems, procedures, steps, logic blocks, processing, andother symbolic representations that directly or indirectly resemble theoperations of data processing devices coupled to networks. These processdescriptions and representations are typically used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art. Numerous specific details are set forth to provide athorough understanding of the present disclosure. However, it isunderstood to those skilled in the art that certain embodiments of thepresent disclosure can be practiced without certain, specific details.In other instances, well known methods, procedures, components, andcircuitry have not been described in detail to avoid unnecessarilyobscuring aspects of the embodiments. Accordingly, the scope of thepresent disclosure is defined by the appended claims rather than theforgoing description of embodiments.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible,non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on,storing the software and/or firmware.

We claim:
 1. Tangible, non-transitory computer readable medium havingstored thereon program instructions that, when executed by theprocessor, cause a computing device to perform functions comprising:maintaining a database of representative spectral characteristics;receiving particular spectral data associated with a particular playbackenvironment corresponding to a particular playback device; based on theparticular spectral data, identifying one of the representative spectralcharacteristics from the database that substantially matches theparticular spectral data; identifying, in the database, an audioprocessing algorithm based on a) the identified representative spectralcharacteristic and b) at least one characteristic of the particularplayback device; and transmitting, to the particular playback device,data indicating the identified audio processing algorithm.
 2. Thetangible, non-transitory computer readable medium of claim 1, whereinmaintaining the database of representative spectral characteristicscomprises: receiving a plurality of spectral data corresponding to arespective plurality of playback environments; and determining, based onthe plurality of received spectral data, the representative spectralcharacteristics.
 3. The tangible, non-transitory computer readablemedium of claim 1, wherein each recorded audio playback data in theplurality of spectral data comprises a first duration, and wherein therecorded audio playback data from the particular playback devicecomprises a second duration that is less than the first duration.
 4. Thetangible, non-transitory computer readable medium of claim 1, whereinthe particular spectral data comprises recorded audio playback of mediacontent.
 5. The tangible, non-transitory computer readable medium ofclaim 1, wherein the particular playback device is a first particularplayback device, and wherein the program instructions, when executed bythe processor, further cause the computing device to perform functionscomprising: storing an indication of the identified audio processingalgorithm; and transmitting, to a second particular playback devicecorresponding to the particular playback environment, data indicatingthe identified audio processing algorithm.
 6. The tangible,non-transitory computer readable medium of claim 1, wherein the programinstructions, when executed by the processor, further cause thecomputing device to perform functions comprising: causing an indicationof the identified audio processing algorithm to be stored at theparticular playback device.
 7. Tangible, non-transitory computerreadable medium having stored thereon program instructions that, whenexecuted by a processor, cause a playback device to perform functionscomprising: playing back first audio content in a playback environment;recording, via a microphone of the playback device, at least a portionof the played back first audio content; while recording the played backfirst audio content, transmitting the recorded first audio content to acomputing device; receiving, from the computing device, an indicationthat no further recorded audio content is required; based on theindication that no further recorded audio content is required,discontinuing recording the played back first audio content; receiving,from the computing device, data indicating an audio processing algorithmcorresponding to the playback environment; and applying the audioprocessing algorithm while playing back second audio content in theplayback environment.
 8. The tangible, non-transitory computer readablemedium of claim 7, wherein playing back the first audio contentcomprises playing back a pre-determined calibration tone.
 9. Thetangible, non-transitory computer readable medium of claim 7, whereinplaying back the first audio content comprises playing back mediacontent.
 10. The tangible, non-transitory computer readable medium ofclaim 7, wherein transmitting the recorded audio content to thecomputing device further comprises transmitting, to the computingdevice, playback device characteristic information corresponding to theplayback device.
 11. The tangible, non-transitory computer readablemedium of claim 7, wherein the program instructions, when executed bythe processor, further cause the playback device to perform functionscomprising: storing an indication of the audio processing algorithmcorresponding to the playback environment in memory.
 12. The tangible,non-transitory computer readable medium of claim 7, wherein the firstaudio content and the second audio content are different portions of thesame media content.
 13. The tangible, non-transitory computer readablemedium of claim 7, wherein the audio processing algorithm is a firstaudio processing algorithm, and wherein the functions further comprise:at a predetermined duration of time after applying the first audioprocessing algorithm, playing back third audio content in the playbackenvironment; recording, via the microphone of the playback device, atleast a portion of the played back third audio content; while recordingthe played back third audio content, transmitting the recorded thirdaudio content to a computing device; receiving, from the computingdevice, an indication that no further recorded audio content isrequired; based on the indication that no further recorded audio contentis required, discontinuing recording the played back third audiocontent; receiving, from the computing device, data indicating a secondaudio processing algorithm corresponding to the playback environment;and applying the second audio processing algorithm while playing backfourth audio content in the playback environment.
 14. A methodcomprising: playing back, by a playback device, first audio content in aplayback environment; recording, via a microphone of the playbackdevice, at least a portion of the played back first audio content; whilerecording the played back first audio content, transmitting by theplayback device to a computing device, the recorded first audio content;receiving, by the playback device from the computing device, anindication that no further recorded audio content is required; based onthe indication that no further recorded audio content is required,discontinuing recording the played back first audio content; receiving,by the playback device from the computing device, data indicating anaudio processing algorithm corresponding to the playback environment;and applying by the playback device, the audio processing algorithmwhile playing back second audio content in the playback environment. 15.The method of claim 14, wherein playing back by the playback device, thefirst audio content comprises playing back by the playback device, apre-determined calibration tone.
 16. The method of claim 14, whereinplaying back by the playback device, the first audio content comprisesplaying back by the playback device, media content.
 17. The method ofclaim 14, wherein transmitting by the playback device to the computingdevice, the recorded audio content, further comprises transmitting, bythe playback device to the computing device, playback devicecharacteristic information corresponding to the playback device.
 18. Themethod of claim 14, further comprising: storing by the playback device,an indication of the audio processing algorithm corresponding to theplayback environment in memory.
 19. The method of claim 14, wherein thefirst audio content and the second audio content are different portionsof the same media content.
 20. The method of claim 14, wherein the audioprocessing algorithm is a first audio processing algorithm, furthercomprising: at a predetermined duration of time after applying by theplayback device, the first audio processing algorithm, playing back bythe playback device, third audio content in the playback environment;recording, via the microphone of the playback device, at least a portionof the played back third audio content; while recording the played backthird audio content, transmitting by the playback device to thecomputing device, the recorded third audio content; receiving, by theplayback device from the computing device, an indication that no furtherrecorded audio content is required; based on the indication that nofurther recorded audio content is required, discontinuing recording theplayed back third audio content; receiving, by the playback device fromthe computing device, data indicating a second audio processingalgorithm corresponding to the playback environment; and applying by theplayback device, the second audio processing algorithm while playingback fourth audio content in the playback environment.